The effect of field application methods on the diffusion patterns of 1,2-dibromo-3-chloropropane and the correlation of these patterns to control of the root knot nematode species Meloidogyne incognita

Abstract

A technique developed by this author utilizing special field sampling methods and chemical analysis (GLC) was compared to an indicator crop for evaluating four fumigant application methods. This technique enabled the diffusion patterns of 1,2-dibromo-3- chloropropane (DBCP) to be determined under field conditions and was superior to an indicator crop in a replicated field trial. When the four methods of fumigant application were compared, the most efficient method, based on diffusion patterns, was Dow Soil Injection Knives used in conjunction with a bed shaper, next were Dow Soil Injection Knives with a rolling cultivator, followed by a single straight shank with a bed shaper and last, a single straight shank with a rolling cultivator. No significant differences between application methods were obtained in field plots due to non-uniform distribution of nematodes as reflected in the variability between replications. A significant difference between chemical application vs no chemical was obtained. Infectivity and hatching of Meloidogyne incognita stored in water or soil is similar and allowed a water screen to be used in determining nematicide toxicity. Toxicity studies indicate the lethal dose of DBCP to second stage larvae of Meloidogyne incognita is 96 ppm-hrs.